1. Field of the Invention
The invention disclosed herein relates to exploration for oil and gas and, in particular, to applications involving a pulsed neutron generator.
2. Description of the Related Art
In the exploration for oil and gas, it is necessary to drill a borehole into the earth. While drilling of the borehole permits operators to evaluate sub-surface materials and to extract desired hydrocarbons, many problems are encountered.
For example, use of nuclear instrumentation presents significant safety issues for personnel. That is, workers tasked with performing well logging issues are often asked to handle radioactive sources that can cause detrimental health effects if great care is not taken. Further, the responsibility for complying with regulation governing the handling of sources of ionizing radiation can be a great burden.
One example of a hazardous instrument is that of a logging instrument that uses a cesium-137 (Cs-137) source. Typically, the Cs-137 source is of a considerable strength. Accordingly, the cost of maintaining the source, the safety issues, and the additional tooling required to support use of the Cs-137 source can make such implementations expensive.
Therefore, what are needed are methods and apparatus that provide for reduced health and safety issues and cost when performing well logging with nuclear instrumentation. Preferably, the methods and apparatus provide for reductions in source terms associated with such instrumentation.